A precarious predicament or generally any situation where the best option is hard to find/ not at all enjoyable.
The present war the United States is engaged in in Iraq is a jar of pickles.
Any situation that you normally would not over-react to, but since you're already under a lot of stress from other situations, you blow it out of proportion.
Why won't this DVD play?!?!?" "Dude, take it easy, it's just a movie." "I know, I'm sorry. I've just been under a lot of stress with work and my girlfriend, and this was just another nail in the coffin. No biggie, just a jar of pickles.